This invention relates to multihull boats and sailing craft. More particularly, but not exclusively, this invention relates to a twin hull boat that is connected by a pivotally mounted beam or beams.
Although multihull boats, particularly sailing yachts, have many performance advantages over monohull boats, multihull boats can take up significant space in marinas due to the distance between hulls. It can also be difficult to fit a catamaran or trimaran in a marina designed for monohull boats. Further, land transportation of multihull boats can be difficult due to the large width of the boat.
Multihull sailing vessels are known to outperform monohull sailing boats in all but the lightest of conditions. One disadvantage of multihull boats has been the difficulty of righting the vessel after it has been capsized. This can be a disturbing feature in open sea travel when a failure to right a vessel can be potentially fatal.
Modern multihull vessels have become lighter in design due to the use of modern fibre composite materials. Although these materials have many advantages, one disadvantage is that a lighter multihull vessel can be more prone to capsizing than a heavier vessel. This can increase the previously mentioned risk of capsizing in open bodies of water.
It is an object of the present invention to provide a multihull boat which overcomes at least some of the abovementioned problems, or which provides the public with a useful choice.
According to a first broad aspect of the invention there is provided an apparatus for attachment to a multihull boat, the apparatus including a beam means substantially transversely associated with at least a first hull and a second hull, the first hull and the second hull being substantially laterally opposed and each hull having a longitudinal axis in the direction of travel of the boat, the beam means being pivotably connected to a first hull or adjacent a first hull to allow for horizontal rotational movement of the first hull, the beam means being pivotably connected to a second hull or adjacent a second hull to allow for horizontal rotational movement of the second hull, and wherein the beam means is adapted to enable the first hull and the second hull to pitch independently of the other.
Preferably the beam means is adapted to enable the hulls to rotate 360 degrees with respect to each other. Desirably the beam means includes a first beam pivotably connected to the first hull and a second beam pivotably connected to the second hull, and a beam joint means positioned between the first hull and the second hull that enables the first beam and the second beam to rotate relative to each other such that the first hull and the second hull pitch independently of the other.
Advantageously the beam joint means includes a releasably attachable securing means retaining the first beam and the second beam in pivotable association and preventing, in use during movement on water, the first hull and the second hull from being drawn together.
When the multihull boat incorporates a sailing hull, preferably the first hull is provided with a mast that is pivotably connected to the hull to allow for vertical rotational movement of the mast, and wherein the beam means is pivotably connected to the mast to enable vertical rotational movement of the beam means.
Desirably the first hull is adapted to form a mast support section, the mast support section being associated with the mast above the pivot connection of the first beam to the mast.
Preferably the mast is tubular and pivotably connected to a cylindrically shaped cavity in the first hull, and wherein a tubular sleeve is fitted between the mast and the cavity and adapted with bearing means to increase the free substantially vertical rotational movement of the mast and the first beam. Desirably the sleeve and the first beam are permanently attached.
Optionally the first beam and the second beam are pivotably connected to a rotational housing located in a suitable position along the beam means to enable the first beam and the second beam to move from a first extended position being substantially transverse to the longitudinal axes of the first hull and the second hull to a second folded position to bring the first hull and the second hull together. Preferably the rotational housing is a bearing housing, and the location of the housing is substantially adjacent a central position between the first hull and the second hull.
Additionally the first hull and the second hull are adapted to interfit in a nesting arrangement when the first hull and the second hull are brought together in the second folded position of the first beam and the second beam.
Desirably the apparatus incorporates hull stabilising means provided between the beam means and the first hull and the second hull, the stabilising means being four flexible stays or rigid struts, or a combination thereof, each said stay or strut being connected at one end to the beam means and the other end being connected to either fore or aft of the first hull or the second hull. Alternatively, the apparatus further includes hull stabilising means provided between the beam means and the first hull and the second hull, the stabilising means being at least two rigid struts, each said strut being connected at one end to the beam means and the other end of at least one strut being connected to either fore or aft of the first hull and at least one strut being connected to either fore or aft of the second strut. Optionally at least two of the stays or struts are releasably attachable to either the first hull or the second hull or the beam means.
According to a second broad aspect of the invention there is provided a self tacking sailing apparatus for use with a jib set on a mast, including a first elongate boom being attached at one end to a suitable first pivot point below the jib and fore of the mast and the other end is associated with the clew of the jib, and a second elongate boom is attached at one end to a suitable second pivot point on the mast and the other end is associated with the clew of the jib and the other end of the first boom.
Preferably the first boom and the second boom are rigid, and wherein the other end of the second boom is pivotably attached to the other end of the first boom, and wherein a rope is attached at one end to the clew of the jib and passes through a slot and pulley in the first boom adjacent the other end of the first boom, and through a guide member positioned at a suitable position along the first boom, the rope then passing through a second guide member positioned at a suitable fixed point below the jib and fore of the mast and aft of the one end of the first boom, the rope is then cleated by a rope retaining means.
Alternatively the first boom and the second boom are rigid, and wherein the one end of the first boom is attached to a sliding member within an elongate sliding means below the jib and fore of the mast and the other end of the first boom is pivotably connected to the other end of the second boom, and the one end of the second boom is attached to a sliding member within an elongate sliding means positioned on the mast.
Preferably the one end of the first boom is associated with an elongate third boom, the third boom extending aft of the main sail and for of the jib and being pivotably attached to a mast and rotatable in a plane substantially perpendicular to the longitudinal axis of the mast. Advantageously the pivotable connections of the beam means to the first hull and the second hull are provided with bearing means. Further, all the pivotable connections may incorporate ring bearings.
According to a third broad aspect there is provided a multihull boat with a first hull and a second hull, the first hull and the second hull being substantially laterally opposed and each hull having a longitudinal axis in the direction of travel of the boat, a beam means being substantially transversely associated with the first hull and a second hull, the beam means being pivotably connected to a first hull or adjacent a first hull to allow for horizontal rotational movement of the first hull, the beam means being pivotably connected to a second hull or adjacent a second hull to allow for horizontal rotational movement of the second hull, and wherein the beam means is adapted to enable the first hull and the second hull to pitch independently of the other.